[whatwg] Start position of media resources

Ralph Giles giles at xiph.org
Tue Apr 7 07:26:31 PDT 2009

On Tue, Apr 7, 2009 at 1:26 AM, Silvia Pfeiffer
<silviapfeiffer1 at gmail.com> wrote:

> For example, take a video that is a subpart of a larger video and has
> been delivered through a media fragment URI
> (http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-reqs/).
> When a user watches both, the fragment and the full resource, and both
> start at 0, he/she will assume they are different resources, when in
> fact one is just a fragment of the other.

There is a ui problem here, in that the 'seek bar' control typically
displayed by web video players has finite resolution. It works great
for short-form clips a la YouTube, but a 30 second segment of a two
hour movie amounts to a few pixels. Displaying such a fragment in the
context of the complete work makes a linear progress bar useless for
seeking within the fragment itself, everything having been traded for
showing that it's part of a much larger resource. Never mind that a
temporal url can equally well reference a five minute section of a
20000 hour webcam archive.

Showing a fragment in context is helpful, not just for the time
offset, but cue points, related resources, and so on. The default
controls the browser provides can't encompass all possible context
interfaces, so perhaps the focus here should be on what is necessary
to enable scripts (or browser vendors) to build more complicated
interfaces when they're appropriate.


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